1. Technical Field
This invention relates to winches for snowmobiles and other track-driven snow vehicles, particularly to a winch that harnesses the power of a snowmobile's engine to close the relative distance between the snowmobile and some other object, as when attempting to free the snowmobile after it has become stuck in soft snow.
2. Background
Under ordinary conditions, a snowmobile propels itself forward by means of a rotating track, with the weight of the snowmobile supported by the snow over which it travels. On hard-packed snow, such as the snow found on a groomed trail, the rotating track easily gains sufficient traction to propel the snowmobile forward. However, in soft snow the rotating track may begin to dig into the snow, sinking the rear end of the snowmobile and slowing its forward progress. As the snowmobiler applies more power to the engine, the rotating track digs itself further into the snow, until the snowmobile's forward progress is arrested and the snowmobile is firmly mired in the snow. When snowmobilers become stuck in this fashion, as they frequently do, they usually resort to one of the following four methods to free the stuck snowmobile: repositioning the snowmobile; tramping a trail; using a portable, hand-operated winch, commonly known as a cable hoist/puller; or using an electrically operated winch.
Each of these methods is described below, along with the disadvantages and limitations of each.
The first method to free a stuck snowmobile is simply to reposition it. Repositioning the snowmobile is the most common and most basic of the four methods. After miring a snowmobile in soft snow, the snowmobiler grasps the lift bar at the rear of the snowmobile and then lifts the rear end of the snowmobile up and out of the snow, repositioning the track a few inches to the left or right of its previous position. The snowmobiler then grasps the lift bar at the front of the snowmobile and lifts the front end up and out of the snow, repositioning the front end a few inches to the left or right of its previous position. In most instances, the snowmobiler must also reposition the skis of the snowmobile to align them with the snowmobile's new position. To lift the snowmobile and reposition the skis, the snowmobiler must often use his or her hands and feet to dig in the snow, in order to make room for the repositioned snowmobile and to provide a firm surface on which the track can gain traction.
The disadvantages and limitations of this method are described below.
The method is time-consuming. Quite often, the snowmobiler must move the front and rear end of the snowmobile to a variety of new locations, repositioning the snowmobile's skis each time, before the snowmobile can gain sufficient traction to propel itself forward.
The method is laborious. Because a typical snowmobile weighs upwards of 400 pounds, repositioning it requires substantial physical strength. For snowmobilers who lack the necessary physical strength, the method is of no use.
The method can quickly tire even those snowmobilers who are in good physical condition. In addition, the exertion required by this method--and the resultant fatigue--increases the likelihood that the snowmobiler will suffer from hypothermia, subnormal temperature of the body.
The method requires that the snowmobiler spend a considerable amount of time digging in the snow and walking through the snow, increasing the likelihood that the snowmobiler will suffer from frostbite or hypothermia.
In spite of the snowmobiler's best efforts, the repositioning may not free the snowmobile. Because the snowmobile is usually surrounded by soft snow, repositioning may simply allow the snowmobile to dig itself in once more, this time in a new location.
Another common method of freeing a stuck snowmobile is for the snowmobiler to tramp a trail in the soft snow. The snowmobiler wades back and forth through the snow that lies between the stuck snowmobile and some firm surface, such as a groomed trail, tramping down the soft snow to create a trail. If the snow along the tramped trail is sufficiently compacted, the snowmobile may be able to proceed on its own power.
The disadvantages and limitations of this method are described below.
The method is time-consuming and laborious, requiring substantial physical strength and good physical condition on the part of the snowmobiler.
The method can quickly tire even those snowmobilers who are in good physical condition. In addition, the exertion required by this method--and the resultant fatigue--increases the likelihood that the snowmobiler will suffer from hypothermia.
The method requires that the snowmobiler spend a considerable amount of time digging in the snow and walking through the snow, increasing the likelihood that the snowmobiler will suffer from frostbite or hypothermia.
Once the snowmobiler has tramped the trail through the snow, the snowmobiler must use physical strength alone to pull the machine forward onto the tramped trail. Pulling the snowmobile forward requires substantial physical strength; for snowmobilers lacking this physical strength, the method is of no use.
Finally, this method works only if the snow in the tramped trail is compacted enough to support the weight of the snowmobile and thus allow its track to gain traction.
A third method for freeing a stuck snowmobile is to use a portable, hand-held winch. Among their gear, some snowmobilers carry a portable, hand-operated winch, commonly known as a cable hoist/puller. Through a combination of physical and mechanical power, the hand-operated winch can be used to free a stuck snowmobile. To use the portable, hand-operated winch, the snowmobiler first attaches the winch to the snowmobile by means of a hook attached to one end of the winch. A similar hook, located at the end of the winch's steel cable, enables the snowmobiler to attach the cable to a tree, a tree stump, a fence post, another snowmobile, or some other solid and secure object. A lever located on the frame of the winch transfers the snowmobiler's physical power to a set of gears encased in the frame. As the snowmobiler works the lever back and forth, the gears turn. As the gears turn, the cable winds around a spool, pulling the snowmobile forward.
The disadvantages and limitations of using a typical hand-held winch are described below.
Using a typical hand-held winch can be as time-consuming as repositioning the snowmobile or tramping a trail. In addition, using a typical hand-held winch requires that the snowmobiler possess sufficient physical strength to operate the lever on the winch. Depending on the size of the hand-held winch and the weight of the snowmobile, the snowmobiler may find that he or she is unable to exert enough pressure on the lever to pull the snowmobile forward.
A typical hand-held winch weighs between 4.5 kg and 6.8 kg, adding significantly to the weight of the snowmobile and thereby negatively affecting the snowmobile's performance, handling, and stability.
The cable on a typical hand-held winch is 3.7 m long, limiting the number of situations and the variety of situations in which it can be used effectively. Because it is a fairly complex piece of equipment, a typical hand-held winch is subject to mechanical breakdowns and failure of its individual parts. Because it is a fairly complex piece of equipment, a typical hand-held winch requires some maintenance, primarily regular cleaning and oiling, to ensure that it operates properly and reliably.
A typical hand-held winch measures 61 cm L by 7.6 cm W by 7.6 cm H. As such, it is too large to fit into a snowmobile's trunk, the storage area located in the rear of the seat. On some snowmobiles, a typical hand-held winch may fit in a storage area located under the seat; however, very few snowmobiles have a storage area under the seat. In addition, a typical hand-held winch is too large to be carried in standard saddlebags. Finally, the bulk of the hand-held winch reduces a snowmobiler's ability to carry other gear, including such commonly carried items as extra clothing, food, and survival equipment.
To overcome some of the disadvantages and limitations of the three methods described above, some snowmobilers have mounted to their snowmobiles an electrically powered winch, of the sort occasionally found on three- and four-wheeled all-terrain vehicles (ATVs). Operating on similar principles as does a hand-held winch, an electrically powered winch enables the snowmobiler to attach a steel cable to a tree, a tree stump, a fence post, another snowmobile, or some other solid and secure object, and then use the winch's power to pull the snowmobile forward a few feet.
The disadvantages and limitations of using a typical electrically powered winch are described below.
A typical winch of this sort weighs between 6.8 kg and 9 kg, adding significantly to the weight of the snowmobile and thereby negatively affecting the snowmobile's performance, handling, and stability.
Because most snowmobiles are not designed to carry a battery, a battery to power the winch must be added to the snowmobile. A typical battery weighs between 1 kg and 1.4 kg, adding significantly to the weight of the snowmobile and thereby negatively affecting the snowmobile's performance, handling, and stability.
Because most snowmobiles are not designed to carry a battery, a snowmobiler wishing to use an electrically powered winch must fabricate a battery mounting bracket in the engine compartment. Installing a typical battery, which measures 20 cm L by 13 cm W by 18 cm H, reduces the snowmobiler's ability to carry other gear, including such commonly carried items as spare parts and tools.
Because snowmobiles are not designed to carry electric winches, the snowmobiler must either fabricate a mounting bracket or purchase a mounting bracket designed for an ATV. In either case, attaching the winch to the snowmobile requires a high degree of mechanical skill. In addition, fabricating a mounting bracket or modifying an ATV bracket can lead to some loss of the snowmobile's performance, handling, and stability, depending on how the bracket is fabricated and how it is attached to the snowmobile.
Electrically powered winches are highly dangerous. A typical electrically powered winch has a working load of up to 499 kg. Generating enough force to pull 499 kg places considerable strain on the winch's steel cable and on any hardware attached to the cable. If the cable or the hardware breaks, the cable or the hardware can come flying back toward the snowmobiler at a high rate of speed. The snowmobiler can reduce the danger of using an electrically powered winch by operating the winch with a hand-held remote-control unit, which enables the snowmobiler to stand some distance from the electrically powered winch. Of course, the remote-control unit adds to the weight of the snowmobile and also reduces the snowmobiler's ability to carry additional gear.
The cable on a typical electrically powered winch is 7.6 m long, limiting the number of situations and the variety of situations in which it can be used effectively. Because it is a highly complex piece of equipment, a typical electrically powered winch is subject to mechanical breakdowns, electrical shorts, and failure of its individual parts. Because it is a highly complex piece of equipment, a typical electrically powered winch requires considerable maintenance to ensure that it operates properly and reliably.